Industrial Field of the Invention and Related Art
This invention relates to an optical endoscope having an ocular portion and provided with an image signal transmission cable.
Endoscopes have in recent years been widely used to enable the affected parts of a body to be observed without the necessity for cutting the same in the body cavity, and, if necessary, treatment can be conducted with the use of tools suitable for the treatment required.
An electronic type of endoscope (abbreviated as "electronic endoscope" hereinafter) which employs a solid imaging device as an imaging means has in recent years been put into practical use. In such endoscopes, the endoscope image can be easily displayed on a monitor and recording and reproduction of the image can also be conducted easily.
In an optical endoscope using an image guide (also can be called "fiber scope"), recording and reproduction of the endoscope image can be conducted with the use of an external TV camera.
A conventional type of endoscope on which an external TV camera is mounted is shown in FIG. 1.
Referring to FIG. 1, in a fiber scope 601, image of an object is transmitted to a handling portion 603 of an endoscope through an image guide 602, and illuminating light is transmitted to the object through a light guide 606 which passes through a light guide cable 605 connected to a light source device 604. An optical image obtained through the image guide 602 is imaged on an imaging surface of a charge coupled device which functions as a solid imaging device (abbreviated as "CCD" hereinafter) 609 by means of an optical imaging system in an external TV camera 608 connected to an ocular portion 607 of the fiber scope 601. The optical image imaged on the CCD 609 is photoelectrically converted, and is input to a signal processing circuit 611 where it is signal-processed and output as an image signal. This image signal is transmitted to a camera control unit 613 through a plurality of transmission cables 612 that pass through a signal cable 610. A plurality of power cables (omitted from the illustration) through which power can be supplied from the camera control unit 613 to the external TV camera 608 are further passed through this signal cable 610.
The above-described camera control unit 613 converts the image signal into, for example, an NTSC combined image signal, and which is input to a TV monitor 614 so that the image of the object may be displayed on the screen of the TV monitor 614.
As shown in FIG. 1, in the conventional example, the signal cable 610 through which the transmission cable 612 for transmitting an image signal is passed connects the external TV camera 608 and the camera control unit 613. The light guide 606 and a light guide cable 605 through which an air flowing pipe or a forceps (omitted from the illustration) are passed connects the endoscope handling portion 603 and the light source device 604.
In the conventional example, since the cables 605 and 610 are respectively extended from the fiber scope 601 and the TV camera 608 which are capable of being separated from each other, these cables can easily get caught during usage. Therefore, if the fiber scope 601 is intended to be used solely with the TV camera 608 removed, it is sometimes difficult to completely separate them from each other.
Furthermore, in a case where the TV camera 608 is connected, since the two cables 605 and 610 are extended from two different places, they will inevitably tend to interfere with handling.